Terry Reedy <tjreedy at udel.edu> wrote:
> Nick Craig-Wood wrote:
> > I've noticed with latest python 3.1 checkout (68631) if I have this
> > object hierarchy with a default __init__ in the superclass to be used
> > by the subclasses which don't necessarily need an __init__ it blows up
> > with a TypeError.
> >
> > class Field(object):
>> object is default baseclass, hence not needed
Agreed, but I wanted the code to run with py < 3 also!
> > def __init__(self, data):
> > """Default init for the subclasses"""
> > print("init class=%r, self=%r" % (self.__class__.__name__, self))
> > super(Field, self).__init__(data)
>> This line is the problem: remove it and I believe all is fine.
> Since object()s are immutable, its init cannot do anything as far as I
> know. Deleting this is effectively what you did below.
Yes you are absolutely right - that super is never needed. I don't
know what I was thinking of! Without that the problem disappears.
[snip]
> Perhaps 2.5's object.__init__ just swallowed all args, thus hiding bogus
> calls.
Yes it did which is the fundamental difference in behaviour between
py2 and py3 as far as I can see.
[snip]
> Eliminate bad call.
Check!
(Bashes head against wall!)
Thanks
Nick
--
Nick Craig-Wood <nick at craig-wood.com> -- http://www.craig-wood.com/nick